Re: [PATCH] xen/arm: remove check for generic timer support for arm64

[Julien Grall <julien.grall@linaro.org>]

On 06/02/2014 03:48 PM, Ian Campbell wrote:
> On Mon, 2014-06-02 at 14:07 +0530, vijay.kilari@gmail.com wrote:
>> From: Vijaya Kumar K <Vijaya.Kumar@caviumnetworks.com>
>>
>> arm64 always supports generic timer. So check is not required
>> for arm64. For platforms which supports only aarch64 mode this
>> check always passes and panics
>>
>> Signed-off-by: Vijaya Kumar K <Vijaya.Kumar@caviumnetworks.com>
>> ---
>>  xen/arch/arm/time.c |    2 ++
>>  1 file changed, 2 insertions(+)
>>
>> diff --git a/xen/arch/arm/time.c b/xen/arch/arm/time.c
>> index 4c3e1a6..801c130 100644
>> --- a/xen/arch/arm/time.c
>> +++ b/xen/arch/arm/time.c
>> @@ -138,8 +138,10 @@ int __init init_xen_time(void)
>>          panic("Timer: Cannot initialize platform timer");
>>  
>>      /* Check that this CPU supports the Generic Timer interface */
>> +#ifdef CONFIG_ARM_32
>>      if ( !cpu_has_gentimer )
>>          panic("CPU does not support the Generic Timer v1 interface");
>> +#endif
> 
> Coming at this form a different angle (ignoring feature flags etc), we
> have by this point already been told by the device tree that a generic
> timer is present (we panic if we don't find a node). So this check is a
> bit redundant (I suppose it would catch people with an incorrect DT, but
> I expect we'd figure that out pretty soon even without this check).
> 
> Perhaps we should just remove this check altogether? Or the suggestion
> to #define it to 1 on arm64 would also work.

I though about removing this bit... but I'm not sure if ACPI will give
us the necessary information for the generic timer.

Regards,

-- 
Julien Grall